<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<style type="text/css">
			*{
				margin: 0;
				padding: 0;
			}
            body,html{
            	height: 200%;
            }
            .right_bottom{
            	width: 200px;
            	height: 200px;
            	background-color: red;
            	/*类似绝对定位。只是会定在整个界面不会被滚动条影响*/
            	position: fixed;
            	right: 0;
            	bottom: 0;
            } 
		</style>
	</head>
	<body>
		  <p>我在上面</p>
		  <div class="right_bottom">
		  </div>
	</body>
</html>
